Apparatus and methods for preventing debris from entering a manhole

ABSTRACT

Apparatus and methods prevent debris from entering a manhole by suspending a pan or other component at a position within the manhole and below the top of the manhole. If debris enters the top of the manhole, such as because the manhole cover has been removed, then the pan or other component catches the debris. The pan or other component is releasable from the position within the manhole so that the pan or other component may be removed. Once removed, the pan or other components can be emptied and/or a person may enter the manhole.

TECHNICAL FIELD

The present invention is related to manholes. More particularly, the present invention is related to the prevention of debris from entering and filling a manhole.

BACKGROUND

Most construction sites include manholes that provide access to various underground systems such as sewer systems. The manhole is generally a substantially vertical passage that leads from the top of the manhole at the ground level down to the underground tunnel system. The manhole is generally formed by placing a concrete cone at the top of a vertical riser section to provide the entryway to the passage from the ground level. The hole at the top of the manhole cone is typically at or above ground level, and workers enter the manhole by passing through the hole at the top of the cone.

Manholes are usually covered at the top of the cone by a manhole cover which caps the hole that otherwise provides the entry into the vertical passageway. However, manhole covers are designed to be fairly easily removable so that workers can easily access the manhole. A negative aspect of the manhole cover being easily removable is that it can be inadvertently removed, thereby exposing the manhole. This is especially true on construction sites where construction vehicles are routinely passing over the manhole covers and scraping the ground level with loader buckets, scraper blades, and other attachments used during construction.

When a manhole cover is inadvertently removed, it may go unnoticed or be otherwise unaddressed such that the manhole is exposed for an extended period of time. This results in debris, such as dirt at a construction site, entering at the top of the manhole and falling down the vertical passage until reaching the pipe system at the base of the manhole. This debris begins to pile up within the base and pipe system and up the vertical passage. The debris becomes a blockade to the pipe system and may substantially fill the vertical passageway, thereby interfering with the proper operation of the pipe system and also preventing access to it through the manhole. To restore normal operation of the tunnel system and manhole, the debris must be manually removed at a substantial cost.

SUMMARY

Embodiments of the present invention address these issues and others by providing apparatus and methods that prevent debris from entering and filing a manhole. The apparatus and method include a pan or similar component that is positioned within the manhole and below the manhole cover at the top of the manhole but is releasable from that position. Any debris entering the top of the manhole is caught by the pan or other component rather than falling down the vertical passage and into the tunnel system. The pan or other component may then be removed through the top of the manhole so that the pan may be emptied of any debris and/or so that a person may enter the manhole.

One embodiment is an apparatus for preventing debris from entering a manhole. The apparatus includes means for catching debris. The apparatus further includes means for releasably suspending the means for catching debris within and below a top of the manhole.

Another embodiment is a method of preventing debris from entering a manhole. The method involves releasably suspending a pan within and below a top of the manhole. The method further involves, upon debris falling into the top of the manhole, catching the debris within the pan.

Another embodiment is a method of creating a manhole system that prevents the entry of debris. The method involves installing a mounting structure within and below a top of the manhole. The method further involves suspending a blocking structure from the mounting structure such that the blocking structure is releasably suspended below the top of the manhole cover and is accessible through the top of the manhole.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional manhole leading to a tunnel system where there is nothing to prevent debris from entering the manhole once the manhole cover is removed.

FIG. 2 is a cross-sectional view of a manhole that includes a first illustrative embodiment of the present invention where a pan releasably suspended by a ring prevents debris from entering the manhole once the manhole cover is removed.

FIG. 3 is a cross-sectional view of the manhole of FIG. 2 after the pan has been removed to empty the debris.

FIG. 4 is a top view of a ring of the embodiment of FIG. 2 that is embedded within a manhole cone to suspend the pan within the manhole.

FIG. 5 is a top view of the pan of the embodiment of FIG. 2.

FIG. 6 is a perspective view of the pan of FIG. 5 when mounted within the ring of FIG.4.

FIG. 7 is a cross-sectional view of a manhole that includes a second illustrative embodiment of the present invention where a pan releasably suspended by a plurality of nubs prevents debris from entering the manhole once the manhole cover is removed.

FIG. 8 is a cross-sectional view of a manhole that includes a third illustrative embodiment of the present invention where a pan releasably suspended by a manhole cone prevents debris from entering the manhole once the manhole cover is removed.

FIG. 9 is a cross-sectional view of a manhole that includes a fourth illustrative embodiment of the present invention where a sectional pan releasably suspended by a ring on the underside of a manhole cone prevents debris from entering the manhole once the manhole cover is removed.

FIG. 10 is a cross-sectional view of a manhole that includes a fifth illustrative embodiment of the present invention where a sectional pan releasably suspended by an additional riser on the underside of a manhole cone prevents debris from entering the manhole once the manhole cover is removed.

DETAILED DESCRIPTION

Embodiments of the present invention prevent debris from entering a manhole by suspending a pan or other component within the manhole at a position below the top of the manhole. If the manhole cover is removed, debris entering the top of the manhole is caught by the pan or other component. Accordingly, the debris does not fall down the vertical passageway of the manhole and does not interfere with the functioning of the tunnel system and manhole.

FIG. 1 shows the cross-section of a conventional manhole 100. The manhole 100 includes a vertical passageway leading from the top of the manhole 100 down to a piping system 112 such as a sewer. The vertical passageway is typically established by a manhole cone 104 that forms the top portion of the manhole 100 and also by first a vertical portion 108 known as a riser that leads from the manhole cone 104 down to the manhole base section 109 where the manhole pipe system 112 is located. The manhole cone 104 is typically formed from concrete and while the cone 104 is shown as being concentric, the cone may also be eccentric or there may be a flat top in place of the cone 104. The riser 108 and base 109 may be formed of various piping materials such as concrete or steel. A ladder 110 formed by steps extending from the cone 104 and riser 108 is typically provided to assist a person in climbing up and down within the manhole 100.

The top of the manhole 100 is often at ground level 102 and a manhole cover 106 is typically fixed in place on a standard ring atop the manhole cone 104. However, once the manhole cover 106 is removed, the vertical passageway is exposed and debris and other objects are free to enter the manhole 100 and collect in the base 109 and piping 112, the riser 108, and the manhole cone 104.

FIG. 2 shows the cross-section of one illustrative embodiment for preventing debris from entering the manhole 100. An illustrative mounting structure such as a ring 202 is formed in this case by embedding the ring 202 within the manhole cone 104 such that the ring 202 has an aperture that is substantially concentric with the aperture of the manhole cone 104. The portion of the ring 202 closest to the aperture is exposed to thereby form a ledge within the manhole cone 104.

An illustrative blocking structure is a pan 204 that includes a lip 205 around the upper periphery of the pan. The pan 204 is positioned within the manhole 100 so that the pan 204 fits within the aperture of the ring 202, with the lip 205 of the pan 204 resting on the exposed portion of the ring 202. The pan 204 is effectively suspended in a position within the manhole 100 below the top of the manhole. Furthermore, as shown in FIG. 3, the pan 204 is releasable from the suspended position by lifting the pan 204 from the ring 202. To assist in removing the pan 204 from the ring 202, handles 206 may be formed on the upper periphery of the pan 204.

In the suspended position, the pan 204 blocks further access to the manhole 100 and catches any debris 208 that enters. The pan 204 may be removed through the top of the manhole 100 and emptied as deemed necessary, and when removed, individuals may enter the manhole 100 in the normal fashion. Furthermore, the pan 204 may be placed back into the suspended position within the manhole 100 while individuals climb down into the manhole 100 to protect the individuals from debris 208 falling into the manhole 100.

FIG. 4 shows a top view of the ring 202 of the embodiment of FIG. 2 while FIG. 5 shows a top view of the pan 204, including the lip 205 and handles 206. The ring 202 or other mounting structure may be formed of various rigid materials including but not limited to steel or other alloys of metal. As with the ring 202, the pan 204 or other blocking structure may also be formed of various rigid materials including but not limited to steel or other alloys of metal. As shown in FIG. 6, the pan 204 is suspended by the ring 202 by the lip 205 resting on the portion of the ring 202 that is exposed from the manhole cone.

Returning to FIG. 1, the manhole may incorporate the illustrative embodiment of the present invention by including the ring 202 within the manhole cone 104, such as during manufacture of the manhole cone 104. During manufacture, the mold for the manhole cone 104 may be adapted to allow the ring 202 to reside in a desired position while the concrete mortar is filled around the ring 202 so that the ring 202 is fixed in place within the manhole cone once the mortar hardens.

As one example of construction of the ring 202, the top of the pan 204, and hence the ring 202, may be located approximately 2 inches from the top of the manhole cone 104 to allow clearance for handles 206 and avoid interference with the manhole cover 106. Furthermore, it has been found that for a standard manhole cone 104 which is concrete that is about 4 inches thick, the ring 202 may have a diameter of 33 inches with an aperture diameter of 21 inches where the ring is embedded 3 inches deep into the manhole cone while 3 inches of the ring 202 are exposed to form the ledge. The ring 202 of this example may have a thickness of one-quarter inch or more.

As one example of construction of the pan 204, the ring 202 above the pan 204 may have a diameter of at least 22 inches within an inside diameter of less than 21 inches so that there is a one-half inch overlap of lip 205 to the ring 202. The pan 204 of this example may have a depth of 3 to 4 inches in which to collect debris 208 and may have a thickness of one-eighth inch or more.

FIG. 7 shows a cross-section of a second illustrative embodiment. In this embodiment, an alternative to the ring within the manhole cone 104 has been utilized. Namely, a plurality of nubs 302 have been partially embedded within the manhole cone 104 and the exposed portion of the nubs 302 extend radially within the manhole cone 104 to provide a surface upon which the lip 205 of the pan 204 may rest to thereby suspend the pan within the manhole 100. The pan 204 may then be removed from the manhole 100 as is the case in the previous embodiment.

As an example of construction, the nubs may be placed into the mortar of the manhole cone 104 so that they are fixed in place once the mortar hardens. Additionally, existing manhole cone installations may be retrofitted by drilling and driving the nubs 302 into the manhole cone 104. The nubs may be constructed of materials such as those discussed above for the ring 202. In one example, the nubs 302 may be positioned 2 inches below the top of the manhole cone 104 and may be 6 inches in length with 3 inches embedded and 3 inches exposed. However, it will be appreciated that caution should be exercised in this embodiment to prevent the nubs from becoming a danger to individuals climbing into and out of the manhole 100. The same pan 204 discussed in the example above may then be suspended from the nubs 302.

FIG. 8 shows a cross-section of a third illustrative embodiment. In this embodiment, an alternative to the ring within the manhole cone 104 has also been utilized. Namely, a lip 402 has been formed within the manhole cone 400 to provide a surface upon which the lip 205 of the pan 204 may rest to thereby suspend the pan within the manhole 100. The pan 204 may then be removed from the manhole 100 as is the case in the previous embodiments.

As an example of construction, the lip 402 may be formed in the mold used to shape the mortar of the manhole cone 104 so that the lip is fixed in place once the mortar hardens. In one example, the lip 402 may be positioned 2 inches below the top of the manhole cone 400 and may be 3 inches in width. The same pan 204 discussed in the examples above may then be suspended from the lip 402.

FIG. 9 shows a cross-section of a fourth illustrative embodiment. In this embodiment, the ring 502 is not embedded within the manhole cone 104 but is instead placed on the underside of the manhole cone 104. Thus, the ring 502 is placed between the vertical tunnel 108 and the manhole cone 104. Again, the ring 502 is partially exposed to provide a ledge upon which a lip of a pan 508 or other blocking structure may rest to suspend the pan 508 and allow it to catch debris falling into the manhole 100.

In this embodiment, the pan 508 may be made much larger in diameter than the pan of other embodiments that is mounted higher within the manhole cone 104. However, if the pan 508 is made larger in diameter, the diameter of the pan 508 may exceed the diameter of the top of the manhole cone 104, which is typically two feet. Thus, to allow the pan 508 to be removable so that individuals may enter the manhole 100, the pan 508 may be made sectional so that individual sections may be taken out at a time where each section fits through the top of the manhole cone 104. Thus, section 504 may separate from section 506 so that each of those sections is individually removable through the top of the manhole 100. The sections may be held together through various schemes for interlocking two separate pieces such as using overlapping flanges or other similar techniques.

FIG. 10 shows a cross-section of a fifth illustrative embodiment. In this embodiment, where an additional riser section 114 is placed between the cone 104 and the conventional riser section 108. Here, the riser section 114 does not have an interior diameter the same as that of the cone 104 and riser 108. Instead, the interior diameter is much small, about 26 inches, but could be larger or smaller, and defines an aperture 116. A pan 604 is posited within the aperture 116 such that a lip 605 rests on the edge of the riser 114 forming the aperture. The pan 604 may include handles 606 as in the other embodiments.

As in the embodiment of FIG. 9, if the pan 604 has a diameter greater than that of the topmost inner diameter of the manhole cone 104, then the pan 604 must be sectioned so that it can be removed from the manhole 110. This will typically be the case because the aperture 116 will likely have a diameter at least as large if not larger than the topmost inner diameter of the manhole cone 104 so that an individual may pass through the aperture 116 when climbing down to the base 1 12 as shown in FIG. 1.

While the invention has been particularly shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made therein without departing from the spirit and scope of the invention. 

1. An apparatus for preventing debris from entering a manhole, comprising: means for catching debris; and means for releasably suspending the means for catching debris within and below a top of the manhole.
 2. The apparatus of claim 1, wherein the means for catching debris comprises a round pan having a lip about the periphery of the top of the pan.
 3. The apparatus of claim 2, wherein the manhole is formed by a manhole cone and wherein the means for releasably suspending comprises a ring embedded in the manhole cone with at least a portion of the ring exposed from the manhole cone such that the hole of the ring is substantially concentric relative to the hole of the manhole cone and such that the lip of the pan rests on the exposed portion of the ring.
 4. The apparatus of claim 2, wherein the manhole is formed by a manhole cone and wherein the means for releasably suspending comprises a lip formed in the manhole cone such that the lip defines a hole that is substantially concentric relative to the hole of the manhole cone and such that the lip of the pan rests on the lip of the manhole cone.
 5. The apparatus of claim 2, wherein the manhole is formed by a manhole cone and wherein the means for releasably suspending comprises a plurality of nubs projecting from the manhole cone in a substantially radial direction relative to the hole of the manhole cone such that the lip of the pan rests on the nubs.
 6. The apparatus of claim 2, wherein the manhole is formed by a manhole cone and wherein the means for releasably suspending comprises a ring located on an underside of the cone such that the lip of the pan rests on the lip.
 7. The apparatus of claim 2, wherein the pan includes one or more handles.
 8. The apparatus of claim 1, further comprising a manhole cover that is releasably fixed to the top of the manhole cover.
 9. A method of preventing debris from entering a manhole, comprising: releasably suspending a pan within and below a top of the manhole; and upon debris falling into the top of the manhole, catching the debris within the pan.
 10. The method of claim 9, further comprising: removing the pan containing the debris from the manhole; emptying the debris from the pan; and inserting the emptied pan back into the releasably suspended position.
 11. The method of claim 10, wherein removing the pan comprises grasping handles of the pan to lift the pan out of the manhole.
 12. The method of claim 9, wherein releasably suspending the pan comprises resting a lip of the pan on a lip extending from a manhole cone forming the manhole.
 13. The method of claim 9, wherein releasably suspending the pan comprises resting a lip of the pan on a plurality of nubs extending from a manhole cone forming the manhole.
 14. The method of claim 9, wherein releasably suspending the pan comprises resting a lip of the pan on a lip of a ring located on the underside of a manhole cone forming the manhole.
 15. A method of creating a manhole system that prevents the entry of debris, comprising: installing a mounting structure within and below a top of the manhole; and suspending a blocking structure from the mounting structure such that the blocking structure is releasably suspended below the top of the manhole cover and is accessible through the top of the manhole.
 16. The method of claim 15, further comprising: installing a manhole cone to form the manhole, and wherein installing the mounting structure comprises fixing the mounting structure relative to the manhole cone.
 17. The method of claim 16, wherein fixing the mounting structure relative to the manhole cone comprises placing the mounting structure at a location on an underside of the manhole cone.
 18. The method of claim 16, further comprising: creating the manhole cone, and wherein fixing the mounting structure relative to the manhole cone comprises embedding at least a portion of the mounting structure into the wall of the manhole cone.
 19. The method of claim 18, wherein embedding at least a portion of the mounting structure into the wall of the manhole cone comprises embedding an outer region of a ring within the wall of the manhole cone such that a hole formed by the ring is substantially concentric with a hole formed by the manhole cone.
 20. The method of claim 18, wherein embedding at least a portion of the mounting structure into the wall of the manhole cone comprises embedding a first end of each of a plurality of nubs such that the second end of each of the plurality of nubs extends radially into the hole formed by the manhole cone.
 21. The method of claim 15, wherein resting the blocking structure comprises placing a pan having a lip within the manhole such that the lip rests on the mounting structure to suspend the pan within and below the top of the manhole.
 22. The method of claim 21, wherein placing the pan comprises grasping the pan by one or more handles attached to the top of the pan.
 23. The method of claim 15, further comprising placing a manhole cover atop the manhole. 